Multi-input multi-output antenna structure

Abstract

Provided is a multi-input multi-output antenna structure configured on a substrate, and the multi-input multi-output antenna structure includes two dipole antennas and two second grounded radiators. Each dipole antenna is used for resonating a first frequency band and a second frequency band. Each dipole antenna includes a feed-in radiator and a first grounded radiator. The feed-in radiator has a feed-in end. The first grounded radiator is disposed beside the feed-in radiator and has a first grounded end. The two second grounded radiators are positioned between the two dipole antennas, the two second grounded radiators are separated from the two first grounded radiators and are respectively corresponding to the two first grounded radiators, and a bent gap is formed between the two second grounded radiators.

What is claimed is: 
     
       1. A multi-input multi-output antenna structure configured on a substrate, comprising:
 two dipole antennas, wherein each dipole antenna is used for resonating a first frequency band and a second frequency band, and each dipole antenna comprises:
 a feed-in radiator having a feed-in end; and 
 a first grounded radiator, disposed beside the feed-in radiator, being separated from the feed-in radiator and having a first grounded end; and 
 
 two second grounded radiators, positioned between the two dipole antennas, wherein the two second grounded radiators are separated from the two first grounded radiators, respectively corresponding to the two first grounded radiators and both located between the two first grounded radiators, and a bent gap is formed between the two second grounded radiators. 
 
     
     
       2. The multi-input multi-output antenna structure according to  claim 1 , wherein the width of the bent gap ranges from 0.3 mm to 1 mm. 
     
     
       3. The multi-input multi-output antenna structure according to  claim 1 , wherein the bent gap has two turning positions forming a Z shape. 
     
     
       4. The multi-input multi-output antenna structure according to  claim 1 , having a virtual center, wherein one dipole antenna and the corresponding second grounded radiator can be rotated by 180 degrees around the virtual center as an axis to be overlapped with the other dipole antenna and the other second grounded radiator. 
     
     
       5. The multi-input multi-output antenna structure according to  claim 1 , further comprising:
 two coaxial transmission lines, respectively configured on the two dipole antennas, wherein each second grounded radiator has a second grounded end, a positive end of each coaxial transmission line is connected to the feed-in end of the corresponding dipole antenna, and a negative end of each coaxial transmission line is connected to the first grounded end of the corresponding dipole antenna and the second grounded end of the corresponding second grounded radiator. 
 
     
     
       6. The multi-input multi-output antenna structure according to  claim 5 , wherein the distance between the two coaxial transmission lines ranges from 8 mm to 15 mm. 
     
     
       7. The multi-input multi-output antenna structure according to  claim 5 , wherein the length of each coaxial transmission line ranges from 230 mm to 500 mm. 
     
     
       8. The multi-input multi-output antenna structure according to  claim 1 , wherein the sum of the length of each feed-in radiator and the length of the corresponding first grounded radiator is ½ wavelength of the first frequency band. 
     
     
       9. The multi-input multi-output antenna structure according to  claim 1 , wherein the length of each feed-in radiator is ¼ wavelength of the first frequency band, and the length of each first grounded radiator is ¼ wavelength of the first frequency band. 
     
     
       10. The multi-input multi-output antenna structure according to  claim 1 , wherein the sum of the lengths of the two second grounded radiators is ¼ wavelength of the first frequency band. 
     
     
       11. The multi-input multi-output antenna structure according to  claim 1 , wherein the length of each second grounded radiator is ⅛ wavelength of the first frequency band. 
     
     
       12. The multi-input multi-output antenna structure according to  claim 1 , wherein the first frequency band ranges from 2400 MHz to 2500 MHz, and the second frequency band ranges from 5150 MHz to 5875 MHz. 
     
     
       13. A multi-input multi-output antenna structure configured on a substrate, comprising:
 two dipole antennas, wherein each dipole antenna is used for resonating a first frequency band and a second frequency band, and each dipole antenna comprises:
 a feed-in radiator having a feed-in end; and 
 a first grounded radiator, disposed beside the feed-in radiator and having a first grounded end; and 
 
 two second grounded radiators, positioned between the two dipole antennas, wherein the two second grounded radiators are separated from the two first grounded radiators and are respectively corresponding to the two first grounded radiators, and a bent gap is formed between the two second grounded radiators, 
 wherein the multi-input multi-output antenna structure has a virtual center, and one dipole antenna and the corresponding second grounded radiator can be rotated by 180 degrees around the virtual center as an axis to be overlapped with the other dipole antenna and the other second grounded radiator.